Even a Facebook (NASDAQ:FB) bull like me was taken by surprise with yesterday's 13% pop.

Aren't stocks supposed to go down when the clock runs out on lockup restrictions for pre-IPO shares? Facebook had 773 million shares and 31 million restricted stock units become available for sale on Wednesday. That should have been a recipe for a disaster, but it wound up being one tasty casserole.

"Some will argue that this is why Facebook is untouchable as an investment," I suggested on Tuesday. "I don't see it that way at all. All of this tension and dread make this a great buying opportunity."

See, there's no free lunch -- even for this tasty casserole.

Beware of conventional wisdom
Tech debutantes will always be susceptible to lockup expirations. It's the nature of the niche, especially when we're looking at dot-com rookies that emphasize stock options over salaries as a way to commit employees to the team sport of fishing for success.

When the right amount of time passes after an IPO, the floodgates may very well open after a very hot or very cold offering.

However, Facebook's pop yesterday isn't the first time this year that a stock has soared on the day when a material sum of shares could hit the open market. Yelp (NYSE:YELP) shares soared 23% this summer on the day that its employees and early investors were allowed the first crack at bailing.

There's more to that story than meets the eye, though.

For starters, shares of Yelp took a hit two weeks week earlier when fellow rookie Angie's List (NASDAQ:ANGI) suffered a 16% decline the day that it had its own restrictions eased for early investors. Yelp's stock wound up suffering a 17% hit that entire week.

In other words, investors were already selling ahead of the news. They knew that Yelp's lockup expiration was coming, so investors figured that they would jump out of the moving car before it went over the cliff. Well, that was the cliff.

Another part of the Yelp story that needs to be told is that the pop wasn't sustainable. The stock has surrendered 25% of its value since the unexpected surge on Aug. 29.

Where does that leave Facebook? Well, if you are trying to draw parallels of Yelp's story to what has and will happen to Facebook's stock, you missed the point. Every story is unique. Lockup restrictions are negative events. The increase in a stock's float and the potential for selling are very real. However, the notion that a stock will tank on the day those restrictions ease -- as if employees are calling in sick that day to push out sell orders -- is historically inaccurate.

The lockup restrictions are bad, but it's up to each individual company to deliver on the fundamentals that will want to make insiders and retail investors alike hold on for the long haul.

Once again, there is no free lunch. You're just going to have to buy your own casserole.

A world of opportunity
There's a new premium report on Facebook detailing the opportunities and challenges in store for its shareholders. The report includes a full year of updates, so time's ticking. Click here to check it out now.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.